Question

What is `6+2*8-12+9-:3`?

Answer 1

`6+2*8-12+9-:3=13`

Explanation:

We can use the order as per PEMDAS - parentheses, exponents, multiplication, division, addition and subtraction.

As such, `6+2*8-12+9-:3`

= `6+16-12+3`

= `25-12`

= `13`

Answer 2

`13`

Explanation:

Always count the number of terms first. Each term must simplify to single answer and in the final step we will add or subtract the answers.
Within a term, do the strongest operations first - powers and roots, and then the multiplication and division.
Parentheses are used when a weak operation must be done before a stronger one.

Blindly following PEDMAS, PEMDAS, etc can lead to wrong answers.

`color(magenta)6color(blue)(+ 2 xx 8)color(red)(-12)color(green)(+9div3)" has 4 terms"`

=`color(magenta)6color(blue)(+ 16)color(red)(-12)color(green)(+3)`

It is probably safer to re-arrange the terms to do all the additions first and then the subtractions.

=`color(magenta)6color(blue)(+ 16)color(green)(+3)color(red)(-12)`

=`25-12`

=`13`